A reduction in the rate of disinflation (inflation falling at a slower pace) is validating JPow's August 2023 comment that we should expect rates to remain higher for longer.

For example, consider the following 4-month periods:
May 2023 - August 2023 decrease in Core PCE:
-0.96%October 2023 - January 2024 decrease in Core PCE:
-0.54%So this is weird. Rates were HIGHER after the final hike in August 2023 and yet the rate of disinflation slowed after that point. That is to say, the economy is receiving MORE medicine and yet experiencing a smaller effect. We can't blame money supply, which has been relatively flat for the past 12 months, and we can't blame QT, which was constant the whole time.
Maybe going from 3% to 2% is inherently harder than going from 5.5% to 4.5%? Maybe there's a mathematical or methodological explanation? Or maybe the economy is just running at white hot full speed mode and a 5.5% FFR upper limit plus QT are the only things keeping inflation down in the 3% range?
I once had a small ski boat that would stick its bow in the air and plow its stern through the water when the engine was given full throttle, but then it would eventually "plane out," adopt a more efficient orientation to the water with the bow down, and start quickly skating along the surface. Once on a plane, it would move faster with half the throttle than it was doing at full throttle plowing with the bow up.
Maybe the economy hit "plane" in some way during 2023, and is now accelerating, even as we dialed back the throttle with more restrictive policy. With real overnight rates at about +2.5% we seem to be just barely constraining inflation.
Another vehicular metaphor is that the airplane making a "soft landing" reduces its angle to the ground as the runway approaches, and slows its descent. A soft landing is becoming more likely as the rate of disinflation slows, and our angle of approach declines as we close in on the target.
Maybe the effect of QT has been offset by monetized government deficits ($+315B higher deficit last year vs. 2022 versus -1.14T in QT during 2023) and other factors such as $163B
lent under the BTFP, so that money supply has flatlined.
This caught me by surprise. I expected constant QT to lead to a falling money supply. But instead we are stimulating the economy at the bottom end with increased government spending and loans to banks, while we are restraining inflation by reducing money supply at the top end, through QT. Those effects together seem to be leading us to a very strong economy and well-contained inflation, despite moderately high real interest rates.
This just-right economic configuration could go on for a long time. It is essentially the taking of two medicines at once - a medicine to stimulate the economy and a medicine to keep inflation down. However I didn't expect "higher-for-longer" to mean any rate cuts would be questionable until the end of 2024. Now there's a lot of talk about keeping rates where they are if things are going so well. In a historical sense, a 12-month Federal Funds Rate plateau at 5.25%-5.5% that ended in August 2024 would be consistent with the Fed's behavior in 2006-2007.